~ an enthusiastic meddler exploring photography

Bellows

One of the more intriguing accessories for the Bronica S2A (and other cameras of that family) is the Bellows Attachment Model 2. Like other bellows attachments for other cameras it’s designed mainly for close up photography, allowing the photographer to move the lens further from the film than normally possible, and so focus on objects that are nearer to the film plane than the normal focusing mechanism allows for. However, unlike most other bellows, the front of the bellows holding the lens can be moved vertically and horizontally relative to the camera, and also rotated to produce either vertical “tilt”, or horizontal “swing”. It almost turns the S2A into a view camera, however the lack of the equivalent rear movements limits it a bit too much for that.

I’ve been keeping an eye open for one of these bellows for sometime, but they are rare and therefore somewhat expensive, and so I have been biding my time. However I’ve been lucky and now acquired a almost mint example for a reasonable sum. Here it is showing of some of the lens movement possible.

So why bother? Well aside from the close-up abilities, which I could easily make use of, the tilting and shifting have a lot of potentially interesting and valuable effects.

Shifting allows perspective correction – for example, preventing converging verticals when photographing a tall building. From my first play with this bellows this particular use isn’t easy to pull off, since although the bellows can focus to infinity, the amount of shift is minimal, when the lens is that far back simply because there’s no room for it to move around in the camera body.

Tilting the lens affects the area of the subject field that is in focus. Exactly how it affects it is much too complicated to get into here, but essentially, the region that is in focus is no longer a plane parallel to the film plane, but a wedge shape extending at an angle to the film plane. (If you’re up for some maths see the relevant wikipedia article). Again, you can’t do a lot of tilt when the lens is near to the camera body, but it’s very useful for close up shots. For example:

With no movements used, the bellows lets me get nice and close-up on a small subject. With some lenses true macro (1:1 magnification) is even possible. In this test shot I took you can see that only the little guy on the left is in focus, as is the tabletop he’s standing on to either side of him, and everything else is a nice soft blur. Because the lens was wide-open, the depth of field is very shallow, probably a centimetre or less. Without movements the only way to extend the depth of field would be to stop down the lens, which might be undesirable for a couple of reasons.
Firstly, you need more light, or a longer exposure – either of which might not be possible or practical. Secondly, you might not be able to stop down enough. With my 50mm lens, stopping down all the way to f/22 might still only give a depth of field of 5cm – not enough to cover the whole row. There’s also the issue that everything to either side is now also in sharp focus and might detract from the image.

This second test was taken using a lot of horizontal swing and some sideways shift so that the wedge of focus falls along the line of Lego figures, so that they are all in focus, and yet nothing to either side of the line is. The lens was wide open for this shot, so light wasn’t a problem. I’m sure you can see that there’s a lot of potential use for this kind of thing in still-life type shots. It remains to be seen how much use it is for my more typical landscape subjects.

The only other disadvantage worth mentioning is that at the extremes of shift and tilt, the image circle of the lens becomes an issue. All my Bronica lenses are designed with a 6×6 frame in mind so their image circles don’t cover a great deal outside that. As you get towards the edge of the image circle the image darkens, and the image quality declines due to aberrations. I had a thought that a way around this would be to get hold of a lens designed for a larger format and contrive some sort of adapter, but that’s just a flight of fancy right now.